1. Field of the Invention
The present invention relates to a device integrated into an electronic equipment, for processing an image picked up by a camera.
2. Description of the Background Art
In recent, most of cellular phones each comprise a camera. By displaying an image picked up by the camera on a monitor of a cellular phone, the cellular phone can be used like a digital camera. Further, it is also possible to transfer the image picked up by the camera via e-mail.
In order to have an image pickup function, a cellular phone needs not only an image pickup sensor such as CCD but also a camera control circuit for controlling the image pickup sensor to perform an image pickup operation. In the cellular phone, generally, a main processing chip for performing a main processing of cellular phone and a dedicated chip for controlling a camera are integrated. With such a construction, it is possible to give general versatility to LSI chips.
An image outputted from the image pickup sensor by control of the camera controlling chip is inputted to the camera controlling chip. A display control for the monitor is performed by the main processing chip. This needs a system for transferring the images from the camera controlling chip to the main processing chip. Conventionally, for example, an image is transferred between the camera controlling chip and the main processing chip through serial communication. Alternatively, if the main processing chip has an input interface for a YUV signal, the camera controlling chip is provided with an output interface for the YUV signal, thereby transferring the image.
Patent Document 1, Japanese Patent Application Laid Open Gazette No. 2002-94934, discloses a technique to allow an MPU to independently perform with a control bus unaffected during an operation for processing of an image picked up by a camera is carried out.
The method of transferring an image from the camera controlling chip to the main processing chip through serial communication, however, has a problem of low communication speed. Especially, in the recent cellular phone with camera function, the number of pixels in a picked-up image becomes larger and this has a large effect on transfer time. If the main processing chip comprises no YUV input interface, it is impossible to adopt the method of transferring a YUV signal. Further, since an uncompressed YUV image is transferred, this imposes a load on the main processing chip.
The technique disposed in Patent Document 1 is a technique for constructing a dedicated circuit in which a camera control circuit and a main processor circuit are integrated and has no task of adding a camera function by utilizing a general-type main processing chip, and suggests no method for solving the above problem, i.e., for reducing time for data transfer between the camera controlling chip and the main processing chip.